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feat(repeatWhen): add higher-order lettable version of repeatWhen
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import { Operator } from '../Operator'; | ||
import { Subscriber } from '../Subscriber'; | ||
import { Observable } from '../Observable'; | ||
import { Subject } from '../Subject'; | ||
import { Subscription, TeardownLogic } from '../Subscription'; | ||
import { tryCatch } from '../util/tryCatch'; | ||
import { errorObject } from '../util/errorObject'; | ||
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import { OuterSubscriber } from '../OuterSubscriber'; | ||
import { InnerSubscriber } from '../InnerSubscriber'; | ||
import { subscribeToResult } from '../util/subscribeToResult'; | ||
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import { MonoTypeOperatorFunction } from '../interfaces'; | ||
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/** | ||
* Returns an Observable that mirrors the source Observable with the exception of a `complete`. If the source | ||
* Observable calls `complete`, this method will emit to the Observable returned from `notifier`. If that Observable | ||
* calls `complete` or `error`, then this method will call `complete` or `error` on the child subscription. Otherwise | ||
* this method will resubscribe to the source Observable. | ||
* | ||
* <img src="./img/repeatWhen.png" width="100%"> | ||
* | ||
* @param {function(notifications: Observable): Observable} notifier - Receives an Observable of notifications with | ||
* which a user can `complete` or `error`, aborting the repetition. | ||
* @return {Observable} The source Observable modified with repeat logic. | ||
* @method repeatWhen | ||
* @owner Observable | ||
*/ | ||
export function repeatWhen<T>(notifier: (notifications: Observable<any>) => Observable<any>): MonoTypeOperatorFunction<T> { | ||
return (source: Observable<T>) => source.lift(new RepeatWhenOperator(notifier)); | ||
} | ||
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class RepeatWhenOperator<T> implements Operator<T, T> { | ||
constructor(protected notifier: (notifications: Observable<any>) => Observable<any>) { | ||
} | ||
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call(subscriber: Subscriber<T>, source: any): TeardownLogic { | ||
return source.subscribe(new RepeatWhenSubscriber(subscriber, this.notifier, source)); | ||
} | ||
} | ||
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/** | ||
* We need this JSDoc comment for affecting ESDoc. | ||
* @ignore | ||
* @extends {Ignored} | ||
*/ | ||
class RepeatWhenSubscriber<T, R> extends OuterSubscriber<T, R> { | ||
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private notifications: Subject<any>; | ||
private retries: Observable<any>; | ||
private retriesSubscription: Subscription; | ||
private sourceIsBeingSubscribedTo: boolean = true; | ||
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constructor(destination: Subscriber<R>, | ||
private notifier: (notifications: Observable<any>) => Observable<any>, | ||
private source: Observable<T>) { | ||
super(destination); | ||
} | ||
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notifyNext(outerValue: T, innerValue: R, | ||
outerIndex: number, innerIndex: number, | ||
innerSub: InnerSubscriber<T, R>): void { | ||
this.sourceIsBeingSubscribedTo = true; | ||
this.source.subscribe(this); | ||
} | ||
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notifyComplete(innerSub: InnerSubscriber<T, R>): void { | ||
if (this.sourceIsBeingSubscribedTo === false) { | ||
return super.complete(); | ||
} | ||
} | ||
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complete() { | ||
this.sourceIsBeingSubscribedTo = false; | ||
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if (!this.isStopped) { | ||
if (!this.retries) { | ||
this.subscribeToRetries(); | ||
} else if (this.retriesSubscription.closed) { | ||
return super.complete(); | ||
} | ||
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this._unsubscribeAndRecycle(); | ||
this.notifications.next(); | ||
} | ||
} | ||
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protected _unsubscribe() { | ||
const { notifications, retriesSubscription } = this; | ||
if (notifications) { | ||
notifications.unsubscribe(); | ||
this.notifications = null; | ||
} | ||
if (retriesSubscription) { | ||
retriesSubscription.unsubscribe(); | ||
this.retriesSubscription = null; | ||
} | ||
this.retries = null; | ||
} | ||
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protected _unsubscribeAndRecycle(): Subscriber<T> { | ||
const { notifications, retries, retriesSubscription } = this; | ||
this.notifications = null; | ||
this.retries = null; | ||
this.retriesSubscription = null; | ||
super._unsubscribeAndRecycle(); | ||
this.notifications = notifications; | ||
this.retries = retries; | ||
this.retriesSubscription = retriesSubscription; | ||
return this; | ||
} | ||
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private subscribeToRetries() { | ||
this.notifications = new Subject(); | ||
const retries = tryCatch(this.notifier)(this.notifications); | ||
if (retries === errorObject) { | ||
return super.complete(); | ||
} | ||
this.retries = retries; | ||
this.retriesSubscription = subscribeToResult(this, retries); | ||
} | ||
} |